fix complie warnings

inc/webclient.h

@@ -73,10 +73,6 @@ extern "C" {
 #define web_strdup                      rt_strdup
 #endif
 
-#ifndef web_strndup
-#define web_strndup                     rt_strndup
-#endif
-
 #define WEBCLIENT_SW_VERSION           "2.3.0"
 #define WEBCLIENT_SW_VERSION_NUM       0x20300
 

src/webclient_file.c

@@ -10,6 +10,8 @@
 
 #include <stdint.h>
 #include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
 
 #include <rtthread.h>
 #include <webclient.h>